Posture for the human body can be described with respect to three planes of reference, as shown in FIG. 1A. When the planes' respective mid lines lie perpendicular to each other, the planes divide the body into equal sections, and indicate the body's center of mass at their intersection. For example, a sagittal plane, which is a vertical plane extending from the front of the body to the back, derives its name from the direction of the sagittal structure of the skull. The sagittal plane may also be considered as an anterior-posterior plane. A median plane, or mid-sagittal plane, can divide the body into equal left and right sides. A frontal plane, also known as coronal plane or lateral plane, is vertical to the body and extends from one side of the body to a opposite side of the body. The coronal plane derives its name from the direction of the coronal suture of the skull, and can divide the body into an anterior portion and posterior portion. A transverse plane is horizontal to the body and can divide the body into upper (cranial) and lower (caudal) portions.
Deviations of the body from any of these planes can adversely affect posture and can cause potentially damaging bodily compensations and dysfunctions, which may result in chronic pain for the patient. To correct these conditions, it is desirable that the tilt of the pelvic angle, which is an angle of the Posterior Superior Iliac Spine to the Anterior Superior Iliac Spine, be approximately 10 degrees. If the 10-degree tilt can be achieved, there can be a natural realignment of 90-degree angles of the skeleton relative to the planes of motion.